Composite closure for removable insertion into wine or similar style bottle

ABSTRACT

A closure for a container provides a secure closure for liquid containers while eliminating the disadvantages of traditional cork closures. The closure includes a reduced density core encapsulated by an agglomerated cork layer to which a cork veneer or printed paper or plastic layer is attached. This composite structure provides uniform pressure against the sides of the bottle finish while eliminating the problems normally associated with real cork closures, such as leakage of oxygen in and product out caused by lenticels.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to closures made from bothsynthetic and natural materials used in the sealing/stoppering ofcontainers. In particular, the present invention relates to an improvedcork for liquid containers.

[0003] 2. Description of the Related Art

[0004] The most common material used in the fabrication of wine corksand bottle stoppers is natural cork which is derived from the bark of anoak tree (Quercus Suber) which is grown primarily in Portugal and Spainand to lesser degrees in Algeria and California. Natural cork hasspecial properties, which make it uniquely suited for the production ofwine corks and bottle or jar stoppers. The superior seal of the naturalcork in comparison to recent plastic alternatives is due to theremarkable elastic properties of natural cork. Microscopic inspection ofcork cells has shown them to be hexagonal prisms, having 18 edges and 12vertices on average. Cell walls have also been identified as not beingstraight but having corrugations, which occupy six of the eight walls ineach cell. Each cell has two or three complete corrugations, which givethe cells the appearance of a bellows or concertina.

[0005] The corrugations, for the most part, occur along the radial axisof the prism. The parallel axis being defined as a line running from thecenter of the tree to its closest outer bark surface at a right angle tothe ground. These corrugations cause the cells to fold up duringcompressive deformation such as in the mechanical compression used toinsert them into the neck of a bottle.

[0006] Collapse of the cells along the folds of the cell walls is localto the area of compression and does not necessarily carry through thebody of the cork. The folding of the cells is not stable, however onceit achieves a level of 10% along the area of compressive force an entirelayer will collapse. This phenomenon will carry on throughout the corkuntil the compressive force is lessened or removed or until the cork hassuffered a complete collapse.

[0007] Upon removal of the compressive force, recovery of the collapsedcells of the cork are, for the most part, complete as the deformationcaused by the compressive force are (non-linear) elastic and as such,recover. Man-made, “plastic cork” replacements for natural cork sufferfrom non-uniformity of the density of the structure along withirregularity of the cells structures i.e., bubble size and shape as wellas wall thickness'. These inconsistency issues of “plastic corks” can beseen to manifest themselves in problems which relate to the all “plasticcorks” not being tight enough which can caused leakage to occur or canallow the cork to be pushed out as a result of the pneumatic pressurewhich develops when the cork is inserted into the neck of the bottle.

[0008] The problems associated with the use of “plastic corks” due tothe irregularity or inconsistency issues is further compounded by thetendency of “plastic corks” to take a set after they have been heldunder compression for a period of time. This can lead to leakage if thebottle is subjected to a temperature change, which would increase thefinish or opening diameter of the bottle without adequate time to allowfor expansion of the “plastic cork”.

[0009] Natural corks allow oxygen and other gases to permeate throughthe cork, which may adversely affect the quality or shelf life of theproduct. Similarly, man made corks allow gases to permeate through thecellular body of the man made closures.

[0010] Therefore, there has been and continues to be a need for aneasy-to-use, practical closure for containers which conforms to thecontainer, which can return to its original shape, which prevents theleakage of oxygen and which does not contaminate the product containedin the container.

SUMMARY OF THE DISCLOSURE

[0011] A closure for containers is described which includes a coreelement and a sheathing layer. The core element is preferably fabricatedfrom an extruded olefinic material. The core element is foamed and/orfilled with pieces of cork and preferably has a density in the range of0.2 g/cm³ to 0.8 g/cm³. The sheathing layer is extrusion mounted orlaminated to the core element. If lamination is used, the preferredmethod is thermoplastic hot-melt adhesives however other methods whichare safe for use with food are also acceptable. The sheathing layer isan aggregate of small pieces of cork in a polymer matrix. The closuremay also include a decorative layer adhered to the sheathing layer. Thedecorative layer may be made from a cork veneer. The closure may furtherinclude an outer an outer protective layer, preferably which isextrusion coated to the outer surface of the closure. The protectivelayer may be formed from an olefinic material. If desired, the outerprotective layer consists of a plurality of sublayers such as one ormore oxygen barrier sublayer and one ore more protective layers. Theoxygen barrier layer is preferably made from ethyl vinyl alcohol, nylon,MDX6 nylon, poly acrylonitrile or polyvinylidene chloride. The closurefurther includes end caps which are attached to the ends of the closure.The end caps may be attached using hot melt adhesive, ultrasonicwelding, hot plate welding or heat sealing and preferably include anoxygen barrier material.

[0012] It is therefore an object of the present invention to provide aclosure for containers which conforms to the container.

[0013] It is another object of the present invention to provide aclosure for containers which protects leakage of oxygen through theclosure.

[0014] It is yet another object of the present invention to provide aclosure for containers which resembles currently used closures.

[0015] It is yet a further object of the present invention to provide aclosure for containers which does not collaps upon extended use.

[0016] Finally, it is an object of the present invention to accomplishthe foregoing objectives in a simple and cost effective manner.

DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a cross sectional view of a preferred embodiment of thepresent invention;

[0018]FIG. 2 is a cross sectional view of an alternate embodiment of thepresent invention;

[0019]FIG. 3 is a cross sectional view of an alternate embodiment of thepresent invention; and

[0020]FIG. 4 is a side view of the preferred embodiment of the presentinvention.

[0021] Element List

[0022]12 core element

[0023]14 sheathing layer

[0024]16 adhesive layer

[0025]18 decorative layer

[0026]20 oxygen barrier layer

[0027]22 protective layer

[0028]24 end caps

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0029] The following detailed description is of the best presentlycontemplated modes of carrying out the invention. This description isnot to be taken in a limiting sense, but is made merely for the purposeof illustrating general principles of embodiments of the invention.

[0030] The present invention is a fabricated closure for containingliquids, predominately but not exclusively wine. The closure includes areduced density core encapsulated by an agglomerated cork layer to whicha cork veneer or printed paper or plastic layer is attached. Theadvantage of this composite structure is to provide the uniform pressureagainst the sides of the bottle finish while eliminating the problemsnormally associated with real cork closures, such as leakage of oxygenin and product out caused by tubular channels, called lenticels. Thelenticels are a natural occurrence in cork and their function is toconnect the outer bark with the inner cork material.

[0031] The outer surface of the agglomerated and/or laminated layer isenrobed with an olefinic layer comprised of one or more layers ofplastic materials. The purpose of the different plastic layers are toprovide a functional barrier between the product and the surface of theagglomerated cork, cork veneer or other surfaces which would benefitfrom having an indirect contact with the product. Benefits providedinclude elimination of “cork taint” and the surface in contact with theproduct would be acceptable by the Food & Drug Administration for directcontact with the product and would be organoleptically neutral

[0032] To provide a barrier to the ingress of oxygen thereby minimizingoxidation and significantly increasing the shelf life and quality of theproduct, an oxygen barrier layer may be included. The preferred materialfor this oxygen barrier layer would be ethyl vinyl alcohol (EVOH), butthe following materials could also be used, nylon, MDX6-nylon,polyvinylidene chloride (PVDC), or poly-acrylonitrile.

[0033] Corks made according to the present invention may be decoratedfor product or manufacturer's identification by printing in the flatdirectly onto the cork, paper or plastic veneer that is laminated ontothe agglomerated sheathing and then wound, by way of conventional means,continuously onto the foamed core of the cork. This results in improvedprint quality due to printing on a flat surface as opposed to a roundsurface. Furthermore, a wider selection of print colors is availablebecause the inks will not be in direct contact with the product.

[0034] Endcaps, which match the compression and barrier characteristicsof the fabricated cork body have the ability to have printed, embossedand/or raised lettering and/or designs. The end caps further provide theability to control the ingress of oxygen, CO₂ and other gases into andout of the body of the fabricated cork and subsequently into and out ofthe enclosed headspace area of the container. Further control andmodification of the entrapped headspace gas is accomplished by the useof oxygen absorbers or scavengers blended into one or more layers of theend cap. The oxygen absorbers would be located in layers outboard of theprimary oxygen barrier layer so as to improve their efficiency relativeto the headspace gases.

[0035] The present invention is a fabricated closure for liquidcontainers comprised of an inner core 12 which is preferably fabricatedfrom an extruded olefinic material, which has been foamed and/or filledwith pieces of cork. The density of the olefinic material is preferablyin the range from 0.2 to 0.8 g/cm³. The foamed and/or filled olefiniccore 12 is produced using normal extrusion manufacturing techniquesknown to those experienced in the art and may include direct injectionof a foaming agent (gas) or the use of chemical blowing agents typicallyused for this type of process or both simultaneously. The preferred typeof chemical blowing agents are those in which an endothermic reactioncauses the formation of CO₂ gas. In addition, the endothermic reactionallows for improved control of the bubble size over othernon-endothermic chemical blowing agents. Bubble size and uniformitythroughout the extrudate are important elements in the consistentproduction of acceptable foamed and/or filled cores 12.

[0036] A sheathing layer 14 is extrusion mounted or laminated to theoutside of the foamed and/or filled core 12. The sheathing layer 14, ifextrusion mounted, is preferably an aggregate of small pieces of cork ina polymer matrix. In a variation of the technology, the sheathing layer14 may be cork or agglomerated cork particles supplied in roll form.

[0037] If the sheathing 14 is laminated to the core 12, it is preferablyaffixed to the foamed and/or filled core 12 by means of an adhesive 16deemed acceptable for direct or indirect food contact by the U.S. Foodand Drug Agency. The preferred adhesive 16 materials are thermoplastichot-melt adhesives although other U.S. Food and Drug Agency compliantadhesive materials may be used.

[0038] The sheathing layer 14 may also have a decorative layer 18adhesive mounted to it for decorative purposes. Examples of thisdecorative layer include cork veneers as well as paper or plastic filmsprinted to look like cork. The outer decorative layer 18 of thesheathing layer 14 may also be printed with a logo, design or name of aparticular company, manufacturer, customer or product.

[0039] The agglomerated sheathing 14 compensates for the naturaltendency of the foamed core 12 to take a permanent set. The uniqueability of natural cork to rapidly recover from a radial compressiveload along with its ability to provide a constant and uniform pressureagainst any irregularities commonly found in the finish of glass bottleseliminates the concern over the propensity for the foamed plasticcomponent to take a set. The decorative layer 18, which may be adhesivelaminated to the agglomerated cork-sheathing layer 14, provides anelegant appearance to the shortcomings of plastic corks, providing thepresent cork with the appearance of natural cork. Corks made accordingto the present invention are virtually indistinguishable from a handcut, natural cork. This ability to mimic natural corks applies to thefabricated cork's ability to be inserted into bottle finishes usingautomatic cork insertion equipment. This ease of use also translates tothe consumer's ability to use the traditional corkscrew in thefabricated cork's removal from the bottle.

[0040] In order to protect the wine from contamination from the cork,paper or printing inks, an additional layer or layers may be extrusioncoated over the sheathed (14), foamed and/or filled core 12. The processof extrusion coating is well known in the wire and cable business as thepreferred method of putting a protective, insulating layer to theoutside of a copper or aluminum wire. In fabricated corks the protectivelayer 22 is normally a single material but it may be produced by meansof the coextrusion process to contain multiple layers. Typically, theprotective layer 22 will be an olefinic material, preferably UnionCarbide's FLEXOMER POLYOLEFIN which has been tested to impart noorganoleptic deviation to the product coming in contact with it.

[0041] Another coextruded layer (or layers) 20 which may be included inthe present fabricated cork manufacturing process protects the wine orproduct from the ingress of oxygen, which is normally found within thecellular structure of foamed plastic, as well as within the cellularstructure of agglomerated and natural corks. The position of the oxygenbarrier layer or layers 20 used to control the ingress of oxygen istypically between the sheathing layer 14 and the protective layer 22.

[0042] If required, the oxygen barrier layer 20 made from a materialsuch as ethyl vinyl alcohol, nylon, MDX6 nylon, poly acrylonitrile orpolyvinylidene chloride (PVDC) may be coextruded along with theprotective layer 22. Depending upon the oxygen barrier material chosenand one or more of the materials it must come in contact with, anintermediate material may be extruded or applied between the protectivelayer 22 and the oxygen barrier layer 20 and, if required to improveadhesion between layers, i.e. between the oxygen barrier layer 20 andthe sheathing layer 14. The primary purpose of the intermediate materialis to provide a functional barrier between the product and the oxygenbarrier material 20 as well as to act as a polymer flow compatablizer,commonly referred to as a tie layer.

[0043] On the opposite side, (inside), of the oxygen barrier layer 20there may again be a flow compatabilizing polymer which may becoextruded in combination with the outer protective layer 22, anintermediate tie layer (if one was required), and the barrier resin. Analternative to this method of applying the adhesive which allows theoxygen barrier material to adhere to the laminated sheathing 14 is toapply a suitable adhesive directly to the outer surface of sheathinglayer 14 or surface which the barrier layer must adhere to.

[0044] The end caps 24 of the fabricated present cork are producedseparately by manufacturing a coextruded film or sheet containing anoxygen barrier material layer. The film, once produced, is thermallywelded (heat-sealed) to the ends of the cork.

[0045] In a variant of the end manufacturing method, a single materialcontaining a physical blend of polymeric materials, including an oxygenbarrier material and a chemical blowing agent, is extruded and formedinto end caps by punching the end caps 24 from the sheet. Additionally,end caps 24 can be produced from a monolithic material by means of acompression or injection-molding process in addition to a coextrusionprocess to produce film or sheet from which the end caps 24 would be cutout.

[0046] End caps 24 produced from monolithic materials can have barrierfilms laminated by way of insert molding of the films to the end caps 24or by thermally welding the films to the end caps 24 prior to theirbeing mated to the fabricated cork body. End caps 24 produced by any ofthe above means may have one or more layers foamed to make the end caps24 more malleable for the insertion process.

[0047] Once the end caps 24 have been manufactured they are applied tothe ends of the cork by adhesive means which would include using a USFood & Drug compliant adhesive system with the preferred method being ahot melt adhesive material. Other methods such as ultrasonic or hotplate welding as well as traditional heat sealing methods may also beused. The end caps 24 can also include an active oxygen scavenger systemsuch as Amasorb ABPA-1000 and ABPA-2000 or a food grade iron powder sucha Hoeganaes Corporation's Ancor FG-100. These materials are useful insignificantly reducing the concentration of oxygen in the headspace ofthe filled and sealed (corked) containers.

[0048] While the description above refers to particular embodiments ofthe present invention, it will be understood that many modifications maybe made without departing from the spirit thereof. The accompanyingclaims are intended to cover such modifications as would fall within thetrue scope and spirit of the present invention.

What is claimed is:
 1. A closure for a container, comprising: anolefinic core element; and an agglomerated cork sheathing layersurrounding the core element.
 2. The closure for a container as setforth in claim 1 wherein the core element is fabricated from an extrudedolefinic material.
 3. The closure for a container as set forth in claim2 wherein the core element is foamed with pieces of cork.
 4. The closurefor a container as set forth in claim 2 wherein the core element isfilled with pieces of cork.
 5. The closure for a container as set forthin claim 1 wherein the core element has a density in the range of 0.2g/cm³ to 0.8 g/cm³.
 6. The closure for a container as set forth in claim1 wherein the sheathing layer is extrusion mounted to the core element.7. The closure for a container as set forth in claim 1 wherein thesheathing layer is laminated to the core element.
 8. The closure for acontainer as set forth in claim 1 wherein the sheathing layer islaminated to the core element by means of thermoplastic hot-meltadhesives.
 9. The closure for a container as set forth in claim 1wherein the sheathing layer is an aggregate of small pieces of cork in apolymer matrix.
 10. The closure for a container as set forth in claim 1further comprising a decorative layer adhered to the sheathing layer.11. The closure for a container as set forth in claim 10 wherein thedecorative layer is formed from a cork veneer.
 12. The closure for acontainer as set forth in claim 1 further comprising an outer protectivelayer.
 13. The closure for a container as set forth in claim 12 whereinthe outer protective layer is extrusion coated.
 14. The closure for acontainer as set forth in claim 12 wherein the outer protective layer isan olefinic material.
 15. The closure for a container as set forth inclaim 12 wherein the outer protective layer consists of a plurality ofsublayers.
 16. The closure for a container as set forth in claim 12wherein the outer protective layer comprises: at least one oxygenbarrier sublayer; and at least one protective sublayer.
 17. The closurefor a container as set forth in claim 16 wherein the oxygen barrierlayer is selected from the group consisting of ethyl vinyl alcohol,nylon, MDX6 nylon, poly acrylonitrile and polyvinylidene chloride. 18.The closure for a container as set forth in claim 1 further comprisingend caps attached to the opposite ends of the closure.
 19. The closurefor a container as set forth in claim 18 wherein the end caps include anoxygen barrier material.
 20. The closure for a container as set forth inclaim 1 wherein the end caps are attached using a method selected fromthe group consisting of hot melt adhesive, ultrasonic welding, hot platewelding and heat sealing.